The invention is directed to a method for preparing food product, to a food product, to the use of native potato protein isolate, to a bread improver, and to a dough.
Many food processes are impaired by undesirable and uncontrolled prolonged action of proteases during proofing. The proteases can be endogenous to ingredients in the food product or can be provided by the addition of micro-organisms and/or enzyme preparations.
The prolonged action of proteases is in particular undesirable in food products that are based on dough comprising a leavening agent, such as bread. Proteases can for instance be included in food products based on dough comprising a leavening agent to increase the workability of the dough.
Dough handling and/or dough stability is impaired by the action of proteases during long proofing times. In the proofing process a leavening agent is allowed to leaven the dough (i.e. to lighten the texture and/or to increase the volume). The leavening agent can for example be yeast. The leavening process is much faster when chemical leavening agents are used, such as baking powder, baking soda (also known as sodium bicarbonate), ammonium bicarbonate (also known as hartshorn, horn salt, bakers ammonia), potassium bicarbonate (also known as potash), potassium bitartrate (also known as cream of tartar), potassium carbonate (also known as pearlash), and monocalcium phosphate. In sourdough breads, the flavour is further enhanced by various lactic or acetic acid bacteria.
Gluten is a combination of proteins that forms a large network during dough formation. This network holds the gas in during dough proofing and baking. The strength of this gluten protein network is therefore extremely important for products based on fermented dough or dough using its endogenous proteases. Proteases break down the gluten protein network during proofing. This leads to weak, non-elastic dough and a poor gas holding capacity and relatively low bread volume.
The effect of prolonged activity of proteases on for example the gluten structure can at least partly be countered by adding oxidative enzymes which are capable of cross-linking and strengthen the gluten protein network. No suitable protease inhibitors are available to sufficiently inhibit the action of many types of endogenous flour endoproteases and aminopeptidases. These various proteases have broad ranges of substrate specificities. This makes it difficult to inhibit with a single type of protease inhibitor. The protease inhibitor must be sufficiently unstable. During baking the protease inhibitor must be inactivated to a large extent to avoid unwanted high levels of inhibitor activity such as trypsin inhibitor that may interfere with the digestion of proteins.
Ambroziak et al. (Acta Alimentaria Polonica 1986, Vol. XII(XXXVI), No. 2, 83-90) describe the use of potato products as bread quality improvers. They mention that enzymatically active potato juice can increase the volume of bread and improves crumb properties. However, it cannot be derived from this document which components of the potato juice are responsible for the improvements of the bread quality. Moreover, potato juice comprises undesirable components, such as negatively charged polymers, pectins, glycoalkaloids, and micro-organisms. These components can give rise to a negative off-taste and/or colour formation.
Object of the invention is to at least partly overcome these shortcomings in the prior art.
Further object of the invention is to provide a fermented dough based food product, with improved water holding capacity and/or elasticity.
Yet a further object of the invention is to provide a suitable replacement for commonly used oxidative agents, which require product labelling.